Embodiments of the present invention relate generally to computer network switch design and network management. More particularly, the present invention relates to scalable and self-optimizing optical circuit switching networks, and methods for managing such networks.
Inside traditional data centers, network load has evolved from local traffic (i.e., intra-rack or intra-subnet communications) into global traffic (i.e., all-to-all communications). Global traffic requires high network throughput between any pair of servers. The conventional over-subscribed tree-like architectures of data center networks provide abundant network bandwidth to the local areas of the hierarchical tree, but provide scarce bandwidth to the remote areas. For this reason, such conventional architectures are unsuitable for the characteristics of today's global data center network traffic.
Various next-generation data center network switching fabric and server interconnect architectures have been proposed to address the issue of global traffic. One such proposed architecture is a completely flat network architecture, in which all-to-all non-blocking communication is achieved. That is, all servers can communicate with all the other servers at the line speed, at the same time. Representatives of this design paradigm are the Clos-network based architectures, such as FatTree and VL2. These systems use highly redundant switches and cables to achieve high network throughput. However, these designs have several key limitations. First, the redundant switches and cables significantly increase the cost for building the network architecture. Second, the complicated interconnections lead to high cabling complexity, making such designs infeasible in practice. Third, the achieved all-time all-to-all non-blocking network communication is not necessary in practical settings, where high-throughput communications are required only during certain periods of time and are constrained to a subset of servers, which may change over time.
A second such proposed architecture attempts to address these limitations by constructing an over-subscribed network with on-demand high-throughput paths to resolve network congestion and hotspots. Specifically, c-Through and Helios design hybrid electrical and optical network architectures, where the electrical part is responsible for maintaining connectivity between all servers and delivering traffic for low-bandwidth flows and the optical part provides on-demand high-bandwidth links for server pairs with heavy network traffic. Another proposal called Flyways is very similar to c-Through and Helios, except that it replaces the optical links with wireless connections. These proposals suffer from similar drawbacks.
Compared to these architectures, a newly proposed system, called OSA, pursues an all-optical design and employs optical switching and optical wavelength division multiplexing technologies. However, the optical switching matrix or Microelectromechanical systems (MEMS) component in OSA significantly increases the cost of the proposed architecture and more importantly limits the applicability of OSA to only small or medium sized data centers.
Accordingly, it is desirable to provide a high-dimensional optical circuit switching fabric with wavelength division multiplexing and wavelength switching and routing technologies that is suitable for all sizes of data centers, and that reduces the cost and improves the scalability and reliability of the system. It is further desirable to control the optical circuit switching fabric to support high-performance interconnection of a large number of network nodes or servers.